JP2007142425A - Photonic device having integrated hybrid microlens array - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve a device practically and inexpensively, in which a device including a light emission/detection element such as VCSEL is integrated in one unit with a microlens array. <P>SOLUTION: An IC light emission/detection device 110 in which at least one light emission/detection elements 118-1, 118-2 are formed on an upper flat surface 112 of a substrate 111 so as to be in the same level as the upper surface of the substrate, and a microlens structure 150 in which at least one microlenses 158-1, 158-2 are integrally formed on a lower flat surface 152 of a pedestal 151, and a plurality of legs 155-1, 155-2 are extended therefrom are formed. Then, the structure 150 is mounted on the surface 112 to produce an assembly 100. At that time, the legs 155-1, 155-2 are contacted to corresponding regions 112-1, 112-2 on the surface 112 respectively such that a space from the elements 118-1, 118-2 to the lenses 158-1, 158-2 is kept at a predetermined distance Z1. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to integrated circuit (IC) integrated light emitting / sensing (photonic) devices and the like, and more particularly to an assembly comprising a microlens array arranged to focus incident and outgoing light of such devices.

  Some high-speed printers use a multi-beam laser light source based on a semiconductor laser to enable parallel transmission of print data. The printing speed in such a high-speed printer is limited by the number of laser beams emitted in parallel from the multi-beam laser light source used and the intensity (emitted power) of these laser beams. In early laser-based high-speed printers, edge-emitting devices were used as multi-beam light sources for printing, but the light emission direction in the edge-emitting devices was parallel to the various layers formed during manufacturing, that is, on the upper surface of the device chip. Since the directions are parallel, there is a problem that the upper limit number of laser beams in the formed multi-beam laser array is practically as few as four. For these reasons, VCSEL (Vertical Cavity Surface Emitting Lasers) has been reinstated in more recent laser-based high-speed printers. A VCSEL is a device that emits light in a direction perpendicular to the interface between layers formed at the time of manufacture, and thus in a direction perpendicular to the top surface of the device. Therefore, it is easy to realize a multi-beam laser array, which is attractive as a multi-beam light source for printing. However, the VCSEL has a disadvantage that its emission power is essentially small in relation to use in a high-speed printer. If the output power is small, it takes a long time to transmit sufficient energy with each beam.

  Therefore, sufficiently increasing the optical throughput from each VCSEL element is a major issue in VCSEL-based printing. The low optical throughput, which is the fate of VCSELs, arises from the narrow active area of each VCSEL element, so it is fundamental to obtain high-power single-mode emission from this type of device. Have difficulty. Although various technical studies have been made for the purpose of enhancing the VCSEL emission light and various technological innovations have been born, the current VCSEL emission power is still insufficient, and the printing speed of 180 ppm or more is still insufficient. It has not reached a level that can suitably realize a printer platform that operates in

  Among these, various ideas have been proposed to improve the optical throughput of existing VCSEL arrays that have a relatively high output power so that they can be used effectively in high-speed printing systems. . Among them are the idea of using active cooling, the idea of increasing the effective light magnification by performing thinning scanning while rotating the VCSEL array, and using a microlens array to narrow the beam deflection angle and increase the amount of light. There is an idea to couple the to the optical system.

  Many of the VCSELs used today are based on the idea of using a microlens to narrow the beam deflection angle and thereby compensate for the low output power, using a thin film process. It is manufactured by integrally forming a lens on the back surface of the wafer. FIG. 10 shows an example of an architecture in which microlenses are formed on the back surface of a substrate. Here, the VCSEL forming surface is called a top surface, and the back surface is called a back surface. This approach is beneficial for some applications, but with some major constraints. First, in this architecture, the lens diameter and the lens interval must be increased to the order of several hundred μm. Next, it is important to suppress the error in the distance between the light source (VCSEL element) and the lens (the distance in the vertical direction in the figure) to a problem-free level, but this is precise so that variations or fluctuations in the thickness of the substrate do not occur. Control (and therefore difficult) must be controlled and managed. Furthermore, the substrate must be a substrate that transmits the wavelength used. And the lens formation process by a substrate back surface process must be compatible with the VCSEL formation process. Due to these constraints, it has been difficult or impossible to produce a VCSEL-based printing system at low cost.

  An object of the present invention is to provide a device that integrates and integrates a microlens array into a VCSEL and a method for realizing the same, and that is practical, low-cost, and suitable.

  In order to achieve such an object, in an assembly according to an embodiment of the present invention, (1) a substrate having a flat upper surface and at least one substrate formed on the substrate so as to face above the substrate is provided. An IC light emitting / sensing device having a light emitting / sensing element; and (2) a pedestal whose bottom surface is flat, a plurality of legs protruding from the bottom surface of the pedestal, and a lower surface of the pedestal. A microlens structure having at least one microlens, and (3) further, the light emitting / sensing element is formed by contacting the microlens structure with each of the leg portions and a corresponding region on the upper surface of the substrate. It was decided to mount on the upper surface of the substrate so that the distance from the microlens to the microlens is maintained at a predetermined distance.

  In the assembly according to the embodiment of the present invention, (1) an IC package having a hole and a stepped shelf surrounding the hole, and (2) a light emission / detection device mounted in the hole of the IC package. A light emitting / sensing device comprising a substrate having a flat upper surface and an array of a plurality of light emitting / sensing elements integrally formed on the upper surface of the substrate so as to face above the substrate; 3) a carrier plate and a microlens structure having an array of a plurality of microlenses, and (4) each of the microlens and the light emitting / sensing element so that the hole is covered with the carrier plate. The microlens structure is mounted on the IC package so that the distance from the corresponding one of the light emitting / detecting devices is maintained at a predetermined distance. Scan on or was to be rigidly mounted on the both.

  In the method according to the embodiment of the present invention, (1) a plurality of micro-processes are formed on the lower flat surface of the block-shaped pedestal by a thin film process so that the leg portion protrudes larger than the micro-lens. Forming a microlens structure by forming a lens and a plurality of legs, and (2) a plurality of microlenses so that each of the microlenses is positioned directly above a corresponding one of the light emitting / sensing elements. Positioning the microlens structure above the upper surface of an IC-based light emission / sensing device having an array of light-emitting / sensing elements; and (3) each of the legs of the IC-based light emission / sensing device. Move the microlens structure, the IC light emitting / sensing device or both until it touches a predetermined area on the top surface By executing the step, and it was decided to produce an assembly comprising a (4) The IC of the light emitting / detecting device and the micro-lens structure.

  Hereinafter, an embodiment of the present invention, in particular, a hybrid apparatus in which a microlens is mounted on an IC light emission / detection device will be described. In the following description, a hybrid type apparatus using a VCSEL array is assumed. However, the hybrid type configuration described in the present application may be other types of IC light emitting devices such as light emitting diode arrays and other types of ICs. It can also be applied to arrays of sensing devices such as pin photodetectors, cavity resonance sensors, metal semiconductor metal detectors, avalanche photodetectors, and the like. That is, in the present application, the terms “IC light emission / detection device” or “photonic device” are used to encompass various devices including those described above.

  In addition, the following description is a description of a configuration in the case where the present invention is implemented according to a specific application and conditions required for the application. However, a person skilled in the art (so-called a person skilled in the art) With reference to the description, the present invention can be applied to manufacture an assembly by itself. Further, in the present application, terms indicating directions, such as “up”, “up”, “down”, “down”, “up”, and “down”, are used, but these are relative positions on the drawing. This is to show the relationship and make the explanation easy to understand, and is not intended to limit the absolute positional relationship and the directional relationship in a certain reference coordinate system. In addition, a so-called person skilled in the art will be able to make various modifications to the preferred embodiments of the present invention described below, and the present invention can be implemented in other forms by extracting general principles. It will be possible. Accordingly, the present invention should not be construed as being limited to the embodiments illustrated and described, but rather the maximum technical scope corresponding to the principles of the present invention and the novel configurations described herein. It should be recognized and interpreted as belonging to the invention.

  FIG. 1 shows an exploded perspective view of a VCSEL device 100 including a VCSEL device 110 and a microlens structure 150 according to first to superordinate conceptual embodiments of the present invention. In the drawing, the microlens structure 150 is shown in two ways, a solid line and a broken line. A solid line floating above the VCSEL device 110 indicates a state before mounting on the VCSEL device 110, and a broken line in contact with the VCSEL device 110 indicates a state after mounting.

  The VCSEL device 110 is a conventional IC device that can be manufactured by a known semiconductor manufacturing technique. In general, the VCSEL device 110 is roughly a semiconductor substrate 111 whose upper surface 112 is generally flat, and at least one in the center of the substrate upper surface 112 (see FIG. In this case, four VCSEL elements 118-1 to 118-4 are arranged. When these VCSEL elements 118-1 to 118-4 are collectively referred to, the subscripts 1 to 4 after the hyphen (subscripts assigned to distinguish the four configurations in the figure) are omitted. , VCSEL array 118 or simply VCSEL 118 (use and omission of subscripts are the same for other reference numerals). Each VCSEL 118 is formed on the substrate upper surface 112 or below the substrate upper surface 112 so that the light beam generated by the VCSEL 118 is mainly emitted above the substrate upper surface 112. The VCSEL device 110 further includes a plurality of electrode pads 113 arranged along the peripheral edge of the upper surface 112 of the substrate, and these electrode pads 113 are formed of a linear conductor 114 formed by a known back surface technique. The corresponding ones of the VCSEL elements 118-1 to 118-4 are conductively connected through the corresponding ones. For example, among the electrode pads arranged along the front edge in the drawing, the electrode pad 113-21 is formed by the linear conductor 114-21, and the electrode pad 113-22 is formed by the linear conductor 114-22, and the VCSEL element 118. -2. Of the conductors on the substrate upper surface 112, the linear conductor 114 is preferably covered with an insulating material such as silicon dioxide, but the electrode pad 113 is exposed so that it can be suitably connected to the IC package by a known wire bonding technique. It is better to leave it.

  The microlens structure 150 has a monolithic (semi) transparent block pedestal 151. The lower surface 152 of the pedestal 151 is generally flat, and at least one microlens 158 is integrally formed with the pedestal 151 so as to protrude from the lower surface 152 of the pedestal 151 at the center. The microlens 158 is provided corresponding to the VCSEL 118, and in the illustrated example, there are similarly four (158-1 to 158-4). Again, when collectively called, it is called a microlens array 158 or simply a microlens 158. Further, the pedestal 151 has three or more standoffs 155 (four standoffs 155-1 to 155-4 in the illustrated example), that is, legs. The standoff 155 in this embodiment is formed integrally with the pedestal 151 along the peripheral edge of the pedestal lower surface 152, and is larger than the protruding length of the microlens 158 and protrudes from the pedestal lower surface 152. This is also referred to as standoff array 155 or simply standoff 155 when collectively referred to. Further, in the above description, terms such as “monolithic” and “monolithic formation” are used, and this means that the light-transmitting material (glass, sapphire, plastic, polymer, acrylic, quartz, etc.) forming the pedestal 151 is used. Etc.) can be subjected to micromachining (micro-shape formation) processing such as chemical etching, reactive ion etching, ion milling, plasma etching, mold, and photo-based shape formation to obtain the desired structure. It means you can. The standoff 155 can also be formed of a different material. For example, it can be formed by depositing an appropriate material on the pedestal using a deposition / growth technique such as a screen printing method, a spin coating method, or a spray coating method.

  As shown in the lower half of FIG. 1 and FIG. 2, on the substrate upper surface 112, regions where the standoffs 155 (155-1 and 155-2 in FIG. 2) are brought into contact, that is, standoff contact points 112-1 to 112-. 4 (112-1 and 112-2) are defined. The pedestal 151 in this embodiment is mounted on the substrate upper surface 112 of the VCSEL device 110 so that each standoff 155 contacts the corresponding one of the standoff contact points 112-1 to 112-4. However, it can be said that the standoff 155 is “standing” on the upper surface 112 of the substrate. Since the substrate upper surface 112 and the pedestal lower surface 152 are both flat, and the standoff protrusion length H1 from the pedestal lower surface 152 is the same for any standoff 155, the “pedestal” automatically causes the pedestal lower surface 152 to be Parallel to the upper surface 112 of the substrate. That is, the plane defined by the pedestal lower surface 152 and the plane defined by the substrate upper surface 112 are parallel to each other, and each microlens 158 (158-1 and 158-2 in FIG. 2) and the substrate upper surface 112 The distance is kept at a constant distance Z1. On the other hand, the microlenses 158 are formed so as to be substantially the same as each other (for example, the diameter of each microlens 158 is the same value D1 and the optical characteristics of all the microlenses 158 are substantially the same). Also, they are arranged in a pattern that matches the arrangement of the VCSEL elements 118 on the upper surface 112 of the substrate. Moreover, the microlens distance Z1 depends on the optical characteristics of the microlens 158 and the light beam LB (received in the case of detection) radiated (received in the case of detection) by the VCSEL element 118 (118-1 and 118-2 in FIG. 2). It is determined according to the strength of the broken line with an arrow). Accordingly, the standoffs 155-1 to 155-4 are formed on the pedestal 151 with the same standoff length H1, and the standoffs 155 contact the substrate upper surface 112 at the corresponding standoff contact points 112-1 to 112-4. By mounting the pedestal 151 on the upper surface 112 of the substrate, all the microlenses 158 are automatically and precisely set so that the distance from the corresponding one of the VCSEL elements 118 is the optically optimum distance Z1. Since the positioning is performed, the light transmission amount along the optical axis from each VCSEL element 118 is remarkably improved.

  In this example, the mounting form of the microlens structure 150 on the substrate upper surface 112 of the VCSEL device 110 is a stand-off between the electrode pad 113 arranged at the peripheral portion and the VCSEL element 118 arranged at the central portion. Contact points 112-1 to 112-4 (112-1 and 112-2 in FIG. 2) are determined, a standoff 155 is formed on the pedestal 151 so as to come into contact with the substrate during mounting, and the substrate The microlens structure 150 is mounted on the upper surface 112. In this sentence, the expression “between” the electrode pad 113 and the VCSEL element 118 is used in an axial sense. That is, the virtual line L1 connecting the standoff contact point 112-1 and the standoff contact point 112-2 in FIG. 1 surrounds the VCSEL array 118, and the virtual line L2 connecting the electrode pads 113 is further It surrounds the outside. This relationship, that is, the relationship of the virtual line L1 to the VCSEL array 118 and the virtual line L2, is referred to as “between” the electrode pad 113 and the VCSEL element 118. As will be described later with reference to the second to subordinate conceptual embodiments of the present invention and prototypes thereof, when the peripheral portion of the microlens structure 150 is inside the group of electrode pads 113, the VCSEL device Convenient for performing wire bonding for conductive connection to 110. That is, the process of mounting the VCSEL device 110 in an IC package for a photonic IC, performing wiring by wire bonding or the like, trial-energizing the VCSEL device 110, and then mounting the microlens structure 150 on the IC package is performed. Convenient to do. In this way, not only can the VCSEL device 110 through the photonic IC satisfying all the characteristics of the specification and passing the test and selection be advanced to the value-added lens mounting process. It is also possible to position the microlens structure 150 with respect to the device 110 by some kind of active positioning method. The “certain” active positioning method referred to here means that a photonic IC is energized to emit an optical signal during the positioning process, and the microlens structure 150 is moved relative to the VCSEL device 110 in this state. This means that the positional relationship when the level of the optical signal reaching the light detection unit of the positioning device becomes the maximum is determined to be the optimal arrangement. Thus, prior to positioning the lens structure 150, particularly the microlens 158, with respect to the photonic element such as the VCSEL device 110, the former can be energized. Is important.

  3 and 4 show a perspective external view and a longitudinal section of a VCSEL assembly 200 according to second to subordinate conceptual embodiments of the present invention. The VCSEL assembly 200 is roughly composed of a VCSEL structure 210 and a microlens structure 250. Note that components that are the same as or similar to the corresponding components in the first embodiment described above are identified using the same or similar reference symbols as those used previously.

  As shown in the lower half of FIG. 3 and FIG. 4, the VCSEL structure 210 has a configuration in which the aforementioned VCSEL device 110 is mounted in a conventional IC package 220. In particular, the IC package 220 is configured by a laminated body 221 having a hole 222 formed at the center thereof, and the VCSEL device 110 is mounted in the center hole 222 in the manner shown in FIG. 3 and shown in FIG. In this manner, the solder structure 230 is firmly fixed on the inner bottom surface 225 of the IC package 220. As shown in FIG. 3, the electrode pads of the VCSEL device 110 are conductively connected to the internal electrode pads 223 located in the central hole 222 by bonding wires 240. In the example shown in FIG. 4, the internal electrode pads 223 of the IC package 220 are formed on the stepped shelves 224 in the central hole 222, and the electrode pads 113 of the VCSEL device 110 are respectively connected by the corresponding connection wires 240. Are connected to the corresponding ones. Further, conductive traces such as a conductive trace 229 indicated by a broken line in FIG. 4 are formed in the laminated body 221 everywhere between the insulating material layers by using a well-known technique in the packaging field. These conductive traces are made of, for example, copper, and conductively connect between external electrodes such as solder bumps 227 deposited on the package lower surface 228 and the corresponding internal electrode pads 223. .

  The inventor of the present invention made a final goal to narrow the beam deflection angle of each VCSEL element. It is also said that a VCSEL element 118 that can be manufactured by a process similar to the conventional process is mounted in an IC package 220 that has the same configuration as an IC package that is already widely used and can be manufactured by an existing process. This is to reduce the deflection angle of the light beam LB, that is, the beam deflection angle while maintaining the framework. Hereinafter, a method employed in the embodiment shown in FIGS. 3 and 4 to achieve this will be described in more detail. Therefore, in the following description, this embodiment is optimized for a VCSEL array in which 8 × 4 VCSEL elements that emit light at 780 nm are arranged, and the VCSEL array 118 is further converted to a standard 36-pad surface mount LLC (leadless chip). carrier) It will be described as being contained in a package. That is, for example, a VCSEL array similar to that used in various printers manufactured by Fuji Xerox Co., Ltd., such as DC1256GA, Doccolor 8000, Xerox 4110, etc., is accommodated in an LLC package manufactured by Kyocera Corporation, etc. And the realization method is demonstrated. Furthermore, as a final target, a target of narrowing the beam deflection angle from a typical value of a conventional half-width = 15 ° to a substantial deflection angle = about 8 ° using a hybrid microlens arrangement was set. This target setting influences the detailed configuration of the present embodiment as will be described later. As will be appreciated by those skilled in the art, the present embodiment can be modified, for example, a package or a VCSEL device can be modified by a conventionally unknown structure or method. . For example, in applications that require different things regarding beam shaping, different lens characteristics will be required. The structure or method according to the present invention can be applied to such applications, In that case, necessary modifications should be made. In order to make the explanation concrete and concise, various matters that can be taken in a limited manner will be described in the following description, but this excludes the possibility of modification to the described embodiment, and is also disclosed in a separate patent. It is also not intended that the invention described in the claims can be interpreted in a limited manner. Note that there is no single note.

  As shown in the upper half of FIG. 3 and FIG. 4, the microlens structure 250 includes a block-shaped pedestal 251 and a carrier plate 260. The pedestal 251 has a base portion 252 that is a portion for fastening the pedestal 251 to the carrier plate 260 and a free end 254 that is a portion extending from the base portion 252 and protruding from the carrier plate 260. On the lower surface 152 of this pedestal 251, that is, on the lower surface of the free end 254, a standoff 155 and a microlens array 158 are arranged in the same manner as the pedestal 151 in the first embodiment. 251 is mounted on the VCSEL device 110 so that the stand-off 155 contacts a corresponding region on the substrate upper surface 112, and the distance from the VCSEL element 118 to the microlens array 158 is surely a predetermined distance. ing. The carrier plate 260 has a configuration in which, for example, a central portion 262 of the glass plate is milled or etched to form an opening, and the base 252 of the pedestal 251 can be received and held in the opening. The role of the carrier plate 260 is to seal the central hole 222 of the IC package 220, and the peripheral edge 265 is firmly fixed to the IC package 220 with a small amount of adhesive 270 as shown in FIG. 4. Although this is not essential, a small amount of adhesive 275 may be used to firmly fix the pedestal 251 to the substrate upper surface 112 of the VCSEL device 110. When the carrier plate 260 is formed of, for example, an ultraviolet (UV) transmissive material and a UV curable adhesive is used as the adhesive 270 (and 275), the adhesive 270 (and 275) is UV-exposed via the carrier plate 260. Can be cured by exposure.

  FIG. 5 shows a general flow of a VCSEL assembly manufacturing method according to an embodiment of the present invention. Although the present method will be described herein as manufacturing the VCSEL assembly 200 according to the second embodiment described above, the present method can also be used to manufacture assemblies comprising other light emitting / detecting devices.

  As shown in the upper left part of FIG. 5, the method first manufactures or obtains the VCSEL device (510) and the IC package (512) ahead of its housing, and further places the VCSEL device in the IC package. Implement (514). Here, “manufacturing or obtaining” means that the object of the present invention is to realize a VCSEL-based high-speed printing system without newly developing a high-output VCSEL or developing a newly configured IC package. In particular, the present invention provides a means for that purpose, so that it is possible to use a stock product without newly manufacturing the VCSEL device and the IC package. By doing so, the cost of parts can be further reduced. Also, examples of VCSEL devices and conventional IC packages that can be used are those previously described with reference to FIGS. Furthermore, existing techniques can be used when mounting a VCSEL device in an IC package. For example, a VCSEL device may be soldered on the (inner) bottom surface of the IC package. Also, once the device is assembled, the VCSEL array cannot be physically accessed because the VCSEL array is completely obscured by the microlens structure. Therefore, it is necessary to conductively connect the VCSEL device to the IC package prior to mounting the microlens structure on the assembly consisting of the VCSEL device and the IC package. 3 and 4, the VCSEL device 110 is conductively connected to the IC package 220 using a conventionally known wire bonding technique at this stage prior to mounting the microlens structure 250.

  Further, as shown in the upper right part of FIG. 5, in this method, a microlens array and a plurality of standoffs (legs) are formed on the lower flat surface of the block-shaped pedestal using thin film technology ( 520), making a carrier plate integral with or separate from this (522) and mounting the pedestal on the carrier plate (524) to produce a microlens structure. Either the formation of the microlens array and thus the manufacture of the microlens structure, the manufacture / acquisition of the aforementioned VCSEL device, the manufacture / acquisition of the IC package, and thus the manufacture of the VCSEL device / IC package assembly may be performed first. Both may be performed simultaneously.

  In forming the microlens array in the present embodiment, and thus in manufacturing the microlens structure, an existing microlens formation method can be used. Therefore, if the combination of the VCSEL device and IC package to be used is determined, and the specifications and tolerances relating to the dimensions and focal length are determined, a microlens array is formed (or a compatible microlens array is obtained) and used. Thus, a microlens structure can be manufactured. In the device assumed here, the diameter of the VCSEL element to be used is only 20 μm and the arrangement pitch is only 28 μm. Therefore, it is necessary to satisfy very strict manufacturing tolerances when forming the microlens array. According to the inventor's idea, the microlens formation process and the VCSEL device manufacturing process are not compatible, and neither the microlens manufacturer nor the VCSEL device manufacturer is willing or likely to make both processes compatible. For this reason, in this embodiment, a hybrid system is used in which an assembly of a VCSEL device or an IC package thereof and a microlens array or a microlens structure are separately manufactured, and both are integrated.

  FIG. 6 shows an enlarged photographed image of a prototype pedestal according to the present invention. The arrangement pattern of the microlenses on the pedestal is matched to the arrangement pattern of the VCSEL elements in a corresponding VCSEL device (not shown). In order to form a microlens array to meet stringent manufacturing tolerances related to the positional relationship with the VCSEL element, several severe problems must be overcome. In particular, individual microlenses must be formed with fairly accurate sizes, shapes and relative arrangements. In order to form the microlens array so as to be suitable for the VCSEL device assumed here, according to the inventor's idea, the entire microlens array has a lens diameter tolerance of ˜2 μm, a focal length uniformity of ˜1 μm, and a lens position. The range conditions of accuracy to 0.2 μm and lens forming part substrate flatness (waviness) to 1 μm must be satisfied. Therefore, a microlens array satisfying these conditions was prototyped by micromachining (for example, etching) a block of STIH53 titania glass manufactured by OHARA INC. The cross-sectional shape of the formed microlens was conical, SAG was 3.3 μm, and the focal length at a wavelength = 780 nm was 31 μm. The standoff was formed integrally with the pedestal so as to protrude larger than the microlens, and the position thereof was closer to the periphery than the microlens array. Specifically, the glass material STIH53 manufactured by OHARA INC., Which is the same as the microlens array, was integrally formed so that the microlens distance Z1 in FIG. 2 was 22.3 ± 0.2 μm. As a method for producing a pedestal, a method was used in which a glass material was batch-fired into a single sheet, and the obtained glass sheet was divided along a pedestal boundary line into a plurality of block-shaped pedestals.

  FIG. 7 shows a slightly simplified perspective appearance of the carrier plate in the present embodiment. On the front and back of the carrier plate 260-1, grooves 264 and 266 having a depth about half the thickness of the carrier plate 260-1 are cut so as to intersect at right angles. Accordingly, a through hole 268 is formed in the center portion 262 of the carrier plate 260-1 by the series of grooves 264 and 266. The widths of the grooves 264 and 266 are determined so that the size of the through hole 268 formed by them becomes a size that can receive and hold the pedestal base. In addition, it may replace with such a form and may take the form which perforate | pierces a carrier plate, forms a suitable through hole, inserts and pastes a pedestal. Conventionally, a form in which a cover glass is further mounted on an appropriate IC package on which the VCSEL device is mounted to protect the VCSEL device has been adopted. However, the carry plate 260-1 in this embodiment is used. Is formed as a flat piece made of a light transmissive material such as Corning glass 1737, for example, so that it can function as an alternative to such a cover glass. However, since the pedestal formed of the light transmissive material can travel light inside and outside, if it is desired to avoid this, the carrier plate may be formed of a non-transmissive material.

  FIG. 8 shows a photographed image of the prototype microlens structure according to the present invention. This microlens structure is a structure in which the pedestal created as described above is mounted on the carrier plate prepared as described above. It should be noted that the pedestal base is firmly fixed in the opening in the center of the carrier plate using an adhesive or the like, and that the pedestal free end where the microlens array is formed is separated from the carrier plate. The pedestal is mounted so that it is in position.

  The assembled microlens structure is then positioned so that each microlens making up the microlens array is positioned directly above the corresponding VCSEL element above the top surface of the assembly of VCSEL devices and IC packages. . In this embodiment, as a process for positioning, at least one of the microlens structure and the VCSEL device is mounted on the position adjustable device, and the VCSEL element can be seen through the microlens structure. A magnifying device is arranged above the device, and in that state, the position adjustable device is operated to adjust the positional relationship of the microlens structure with respect to the VCSEL device, and an enlarged image of the microlens is captured through the magnifying device. A process is used that includes the procedure of ending the adjustment once it is found that at least one of the microlenses that make up the array is directly above the corresponding VCSEL element. In FIG. 5, as an example of the flow of steps constituting such a process, an assembly consisting of a VCSEL device and an IC package is mounted on an XYZΘ table as an example of a position adjustable device (530), while a microlens structure is positioned. It shows the flow of mounting on a support chuck as an example of an adjustment device and placing it above the XYZΘ table (535) and positioning the microlens array on the VCSEL array using a microscope as an example of an enlargement device (540). ing. Further, an adhesive may be applied to the stepped shelf at the peripheral edge of the central hole of the IC package (530). However, this adhesive should not be cured for the time being. FIG. 9 shows a simplified configuration example of a device used at this stage, that is, a position adjustment device and an enlargement device. In this figure, a VCSEL assembly 200 comprising a VCSEL device 110 and an IC package 220 is mounted on a table 910 and a microlens structure 250 is held on a chuck 920. The table 910 is a device that can adjust the position of the mounted object (VCSEL assembly 200) by micrometer-type operation of an XYZΘ stage (not shown), and the chuck 920 adsorbs an object by vacuum suction, and the adsorbed object (microlens structure 250) is a VCSEL device. A holder chuck or a support chuck that can be suspended on 110. The table 910 and the chuck 920 are configured to be movable with respect to the objective lens 930 of the microscope integrally with each other and with the mounted object and the adsorbed object. For example, a table 910 and a chuck 920 may be mounted on an XYZ stage (not shown) and the XYZ stage may be operated as appropriate. Further, if the mounted object and the adsorbed object are simply moved together with respect to the objective lens 930, a dedicated XYZ stage is provided so that the chuck 920 can be moved, and the chuck 920 is synchronized with the XYZΘ stage for the table 910 (described above). The XYZ stage may be moved. The table 910 and the chuck 920 can further move the mounted object and the adsorbed object relatively and inspect the positional relationship between them at a high magnification with a microscope (except for the objective lens 930 for the sake of simplicity). It is configured so that it can. That is, while the microlens structure 250 and the VCSEL device 110 are captured in the field of view of the objective lens 930 of the microscope, the table 910 is moved by operating the XYZΘ stage (or the chuck 920 is moved together with or instead of this). It can be moved by operating the XYZ stage). By such an operation, at least one of the microlenses constituting the microlens array on the microlens structure 250 in the enlarged image captured through the objective lens 930 of the microscope is positioned at the VCSEL element. Positioning can be overlaid above the corresponding one of the VCSEL elements on the VCSEL device.

  When precise positioning by such a method is completed and each macro lens constituting the microlens array is positioned immediately above the corresponding VCSEL element, the XYZΘ stage for the table 910 is operated as shown in FIG. Lifts the assembly of the VCSEL device and IC package and contacts the standoff to the top surface of the VCSEL device substrate in the manner described above (550). When the assembly is subsequently lifted, the microlens structure 250 is pushed up, and due to its own weight, the microlens structure 250 is pressed against the assembly. As a result, the microlens structure 250 is self-supported by its standoff (leg), and is precisely with respect to the assembly. Parallelized. At this time, the position in the XY direction can be readjusted or precisely adjusted by operating the table 910 or the chuck 920 to move the assembly with respect to the microlens structure 250. In any case, since the positioning of the microlens array with respect to the laser mesa (VCSEL element) is automatically performed with reference to the laser mesa, importantly, the position of the VCSEL opening (opening of the microlens array) and the corresponding mesa structure are important. The position of the (VCSEL element) coincides with a high accuracy of a misalignment of 0.5 μm or less.

  When the mounting process is completed in this way, as shown in FIG. 5, a microlens for the VCSEL device is applied by applying and curing a UV curable adhesive between the peripheral edge of the carrier plate and the stepped shelf of the IC package. The position of the structure is fixed at the current position (560). If an adhesive has been applied in step 530 performed earlier, the adhesive can also be cured simultaneously. Thus, the VCSEL structure shown in FIG. 4 is obtained. It should be noted that the space between the peripheral edge 265 of the carrier plate 260 and the stepped shelf 224 must be fixed with a small amount of adhesive 270, and therefore somewhat between the carrier plate peripheral edge 265 and the stepped shelf 224. The microlens structure 250 cannot be tilted without this gap, and therefore the standoff 155 cannot be brought into close contact with the substrate upper surface 112 of the VCSEL device 110. In addition, UV for curing the adhesive in this portion is sent from the optical fiber toward the lens holder chuck 920, reflected on the surface thereof, and directed into the IC package 220 of the VCSEL device 110 via the carrier plate 260, for example. After completing the positioning and joining in this way, for example, the gap remaining around the microlens structure 250 may be filled with epoxy and the epoxy may be cured.

  According to the manufacturing method described above, a substrate thickness error and a direction error generated in the VCSEL device due to the manufacture of a VCSEL assembly in which each microlens array is arranged with high accuracy and high reproducibility above the VCSEL array. Despite being, it can be suitably manufactured. That is, first, when mounting the VCSEL device in the surface mount package, since the die attachment process of soldering in the surface mount package with the back surface of the VCSEL device facing down is used as described above, the variation in the solder reflow process As a result, a certain degree of inclination is almost inevitably generated in the substrate (die) of the VCSEL device. In addition, this inclination is different for each package. In addition, since the thickness of the substrate of the VCSEL device does not have a significant effect on the element performance of the VCSEL device itself, avoid controlling and controlling the substrate thickness precisely as in the configuration in which a lens is formed on the back of the substrate. I want. In this method, precise substrate thickness management and control at the time of manufacture is abolished, and the substrate thickness of the VCSEL device is allowed to be different for each device. Since the size, position, orientation, etc. of the VCSEL device are somewhat uncertain due to the substrate tilt, substrate thickness variation, etc., in this method, the reference for the position of the microlens in the Z direction is used as an IC package or device holding / alignment stage. Not on the surface of the VCSEL device. In other words, in a preferred embodiment of the present invention, the standoff (leg) 155 and the VCSEL device 110 are brought into contact with each other, so that manufacturing-induced variation factors such as substrate tilt and substrate thickness variation are absorbed, and the position of the microlens array. Is automatically set to the optimum position based on the surface and position of the VCSEL array.

  Although the present invention has been described above with reference to the embodiment, as is obvious to those skilled in the art, the characteristic configuration of the present invention can be suitably implemented in other forms as well. Those embodiments are included in the technical scope of the present invention without exception. For example, in the above-described embodiment, the number of standoffs (legs) is four, but it may be three or eight. In addition, the surface shape of each microlens may be determined depending on what state, shape, or direction of the light beam is required, and thus various shapes can be used. A spherical surface, an aspherical surface, a cylindrical surface, a toroidal surface, or a weight surface may be used, a prism surface, a diffractive surface, or a facet surface may be used. It may be a free shape. Furthermore, the structures of the microlenses forming the same array may be different from each other, and the arrangement positions of the microlenses on the base material, that is, the pedestal may be the upper surface, the lower surface, or both. The opening shape of the microlens or the cross-sectional shape of the light beam may be non-circular, such as a square, a rectangle, an ellipse, a hexagon, and the like.

FIG. 3 is an oblique view of an assembly having a microlens structure and a light emitting / sensing device according to the first embodiment of the present invention. It is the longitudinal cross-sectional view which showed the assembly shown in FIG. 1 somewhat simplified. It is the exploded view which looked at the VCSEL assembly which has a microlens structure, a VCSEL device, and an IC package from diagonally upward concerning 2nd Embodiment of this invention. FIG. 4 is a longitudinal sectional view showing the assembly shown in FIG. 3 in a slightly simplified manner. FIG. 4 is a process flow diagram showing a method for manufacturing the assembly shown in FIG. 3. It is a figure which shows the picked-up image of the pedestal in the prototype of this invention, especially its micro lens array, and a stand-off (leg part). It is the perspective view which simplified and showed the shape of the carrier plate in 2nd Embodiment somewhat. It is a figure which shows the picked-up image of the micro lens in assembly in the prototype of this invention. It is a disassembled perspective view which shows the example of the manufacturing apparatus of the VCSEL assembly which concerns on 2nd Embodiment. It is sectional drawing which showed the conventional micro lens array integrated type VCSEL array somewhat simplified.

Explanation of symbols

  100 VCSEL device, 110 VCSEL device, 111 semiconductor substrate, 112 substrate upper surface, 112-1 to 112-4 stand-off contact location, 118 VCSEL element or array, 150,250 microlens structure, 151,251 pedestal, 152 pedestal lower surface, 155 standoff or array thereof, 158 microlens or array thereof, 200 VCSEL assembly, 210 VCSEL structure, 220 IC package, 222 center hole, 224 stepped shelf, 260, 260-1 carrier plate, 510 VCSEL device preparation process, 512 IC package preparation process, 514 VCSEL device mounting process, 520 microlens array / pedestal creation process, 522 carrier plate creation process, 524 pedestal Star mounting process, 530 table mounting process, 535 chuck mounting process, 540 positioning process, 550 assembly lifting process, H1 standoff length, Z1 microlens distance.

Claims (3)

An integrated optical radiation / sensing device having a substrate having a flat top surface and at least one light radiation / sensing element formed on the substrate facing the substrate;
A microlens structure having a pedestal having a flat bottom surface, a plurality of legs projecting from the bottom surface of the pedestal, and at least one microlens integrally formed on the bottom surface of the pedestal;
Further, the microlens structure includes the microlens structure so that the distance from the light emitting / detecting element to the microlens is maintained at a predetermined distance by contact between each of the leg portions and a corresponding region on the upper surface of the substrate. An assembly mounted on the top surface of the board. An IC package having a hole and a stepped shelf surrounding the hole;
A light emitting / sensing device mounted in a hole of an IC package, the substrate having a flat upper surface and a plurality of light emitting / sensing devices integrally formed on the upper surface of the substrate so as to face above the substrate. A light emitting / sensing device having an array of sensing elements;
A carrier plate and a microlens structure having an array of a plurality of microlenses;
Further, the microlens structure is configured so that the hole is covered by the carrier plate and the distance between each of the microlenses and the corresponding one of the light emitting / detecting elements is maintained at a predetermined distance. An assembly that is rigidly mounted on an IC package, on the light emitting / sensing device, or both. A microlens structure is formed by forming a plurality of microlenses and a plurality of legs by a thin film process on the lower flat surface of the block-shaped pedestal so that the legs protrude more than the microlenses. Forming step;
Above the upper surface of the IC light emitting / sensing device having an array of a plurality of light emitting / sensing elements, the microlenses are positioned directly above the corresponding ones of the light emitting / sensing elements. Positioning the lens structure;
Moving the microlens structure, the IC light emitting / sensing device or both until each leg contacts a predetermined area on the top surface of the IC light emitting / sensing device;
A method performed to manufacture an assembly comprising the IC light emitting / sensing device and the microlens structure.